Method and apparatus for paging procedures in new radio (nr)

ABSTRACT

Methods and apparatuses are described herein for paging procedures in wireless systems. For example, a wireless transmit receive unit (WTRU) may monitor one or more physical downlink control channels (PDCCHs) for paging resources associated with a first subset of synchronization signal (SS) blocks that corresponds to a first beam tracking area (BTA). On a condition that at least one measurement of at least one beam associated with the first subset of SS blocks is less than a predetermined threshold, the WTRU may transmit, to a base station (BS), a signal indicating a second BTA that is associated with a second subset of SS blocks. The signal includes a physical random access channel (PRACH) resource associated with a second group of SS blocks that corresponds to the second BTA.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 62/519,699, filed Jun. 14, 2017, and U.S. Provisional ApplicationSer. No. 62/500,706, filed May 3, 2017, the contents of which are herebyincorporated by reference herein.

BACKGROUND

In 5G New Radio (NR), to fulfill the high data rate requirements, above6 GHz frequency spectrum have been agreed to use in order to leveragethe large bandwidth. One of challenges in using these above 6 GHzfrequencies may be significant propagation loss, especially in anoutdoor environment due to higher free space path loss in a higherfrequency. In NR, a beam-centric system has been adopted to address thesignificant path loss in a higher frequency since it can compensate pathloss without increasing transmission power. For example, multiple beamsmay be used for initial access and subsequent paging procedures.However, existing paging channels has not been designed based on thebeam-centric system. Moreover, different paging channel resources cannotbe transmitted with more than one beam in the existing paging channels.Thus, it would be desirable to have methods and apparatuses that supportmultiplexing of paging messages for multiple wireless transmit/receiveunits (WTRUs) in a beam-centric system.

SUMMARY

Methods and apparatuses are described herein for paging procedures inwireless systems. For example, a wireless transmit receive unit (WTRU)may receive, from a base station (BS), a configuration of beam trackingareas (BTAs) that associates a set of synchronization signal (SS) blockswith each BTA. The WTRU may select, based on at least one measurement ofat least one beam associated with the set of SS blocks, a first SS blockin a first subset of SS blocks. The WTRU may determine, based on theconfiguration of BTAs, the first BTA associated with the first subset ofSS blocks. The WTRU may then monitor one or more physical downlinkcontrol channels (PDCCHs) for paging resources associated with the firstsubset of SS blocks that corresponds to the first BTA. On a conditionthat at least one measurement of at least one beam associated with thefirst subset of SS blocks is less than a predetermined threshold, theWTRU may transmit, to a base station (BS), a signal indicating a secondBTA that is associated with a second subset of SS blocks. The signal mayinclude a physical random access channel (PRACH) resource associatedwith the second subset of SS blocks that corresponds to the second BTA.The set of SS blocks may comprise the first subset of SS blocks and thesecond subset of SS blocks. An SS block in the set of SS blocks maycomprise a primary synchronization signal (PSS), a secondarysynchronization signal (SSS), and a physical broadcasting channel (PBCH)associated with the SS block.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A is a system diagram illustrating an example communicationssystem in which one or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram illustrating an example wirelesstransmit/receive unit (WTRU) that may be used within the communicationssystem illustrated in FIG. 1A according to an embodiment;

FIG. 10 is a system diagram illustrating an example radio access network(RAN) and an example core network (CN) that may be used within thecommunications system illustrated in FIG. 1A according to an embodiment;

FIG. 1D is a system diagram illustrating a further example RAN and afurther example CN that may be used within the communications systemillustrated in FIG. 1A according to an embodiment;

FIG. 2A is a diagram illustrating an example of timing for hyper frames(HFs);

FIG. 2B is a diagram illustrating an example of paging within hyperframes;

FIG. 3 is a diagram illustrating an example of synchronization signal(SS) blocks within SS bursts;

FIG. 4 is a diagram illustrating an example of association types for newradio-physical downlink control channel (NR-PDCCH) andnew-radio-physical downlink control channel (NR-PDSCH);

FIG. 5 is a diagram illustrating an example of quasi-co-location (QCL)association between SS blocks in an SS burst;

FIG. 6 is a diagram illustrating an example of beam tracking areas(BTAs) for paging monitoring in an SS burst;

FIG. 7 is a diagram illustrating another example of BTAs for pagingmonitoring in an SS burst; and

FIG. 8 is a diagram illustrating an example procedure for updating BTAfor paging monitoring.

DETAILED DESCRIPTION

FIG. 1A is a diagram illustrating an example communications system 100in which one or more disclosed embodiments may be implemented. Thecommunications system 100 may be a multiple access system that providescontent, such as voice, data, video, messaging, broadcast, etc., tomultiple wireless users. The communications system 100 may enablemultiple wireless users to access such content through the sharing ofsystem resources, including wireless bandwidth. For example, thecommunications systems 100 may employ one or more channel accessmethods, such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailunique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM(UW-OFDM), resource block-filtered OFDM, filter bank multicarrier(FBMC), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a RAN104/113, a CN 106/115, a public switched telephone network (PSTN) 108,the Internet 110, and other networks 112, though it will be appreciatedthat the disclosed embodiments contemplate any number of WTRUs, basestations, networks, and/or network elements. Each of the WTRUs 102 a,102 b, 102 c, 102 d may be any type of device configured to operateand/or communicate in a wireless environment. By way of example, theWTRUs 102 a, 102 b, 102 c, 102 d, any of which may be referred to as a“station” and/or a “STA”, may be configured to transmit and/or receivewireless signals and may include a user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a subscription-based unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watchor other wearable, a head-mounted display (HMD), a vehicle, a drone, amedical device and applications (e.g., remote surgery), an industrialdevice and applications (e.g., a robot and/or other wireless devicesoperating in an industrial and/or an automated processing chaincontexts), a consumer electronics device, a device operating oncommercial and/or industrial wireless networks, and the like. Any of theWTRUs 102 a, 102 b, 102 c and 102 d may be interchangeably referred toas a UE.

The communications systems 100 may also include a base station 114 aand/or a base station 114 b. Each of the base stations 114 a, 114 b maybe any type of device configured to wirelessly interface with at leastone of the WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to oneor more communication networks, such as the CN 106/115, the Internet110, and/or the other networks 112. By way of example, the base stations114 a, 114 b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller,an access point (AP), a wireless router, and the like. While the basestations 114 a, 114 b are each depicted as a single element, it will beappreciated that the base stations 114 a, 114 b may include any numberof interconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 104/113, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals on one or morecarrier frequencies, which may be referred to as a cell (not shown).These frequencies may be in licensed spectrum, unlicensed spectrum, or acombination of licensed and unlicensed spectrum. A cell may providecoverage for a wireless service to a specific geographical area that maybe relatively fixed or that may change over time. The cell may furtherbe divided into cell sectors. For example, the cell associated with thebase station 114 a may be divided into three sectors. Thus, in oneembodiment, the base station 114 a may include three transceivers, i.e.,one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and mayutilize multiple transceivers for each sector of the cell. For example,beamforming may be used to transmit and/or receive signals in desiredspatial directions.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet(UV), visible light, etc.). The air interface 116 may be establishedusing any suitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104/113 and the WTRUs 102 a,102 b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 115/116/117 using wideband CDMA (WCDMA).WCDMA may include communication protocols such as High-Speed PacketAccess (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-SpeedDownlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access(HSUPA).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as Evolved UMTS TerrestrialRadio Access (E-UTRA), which may establish the air interface 116 usingLong Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/orLTE-Advanced Pro (LTE-A Pro).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement a radio technology such as NR Radio Access, which mayestablish the air interface 116 using New Radio (NR).

In an embodiment, the base station 114 a and the WTRUs 102 a, 102 b, 102c may implement multiple radio access technologies. For example, thebase station 114 a and the WTRUs 102 a, 102 b, 102 c may implement LTEradio access and NR radio access together, for instance using dualconnectivity (DC) principles. Thus, the air interface utilized by WTRUs102 a, 102 b, 102 c may be characterized by multiple types of radioaccess technologies and/or transmissions sent to/from multiple types ofbase stations (e.g., an eNB and a gNB).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.11 (i.e.,Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperabilityfor Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO,Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), InterimStandard 856 (IS-856), Global System for Mobile communications (GSM),Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and thelike.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, an industrialfacility, an air corridor (e.g., for use by drones), a roadway, and thelike. In one embodiment, the base station 114 b and the WTRUs 102 c, 102d may implement a radio technology such as IEEE 802.11 to establish awireless local area network (WLAN). In an embodiment, the base station114 b and the WTRUs 102 c, 102 d may implement a radio technology suchas IEEE 802.15 to establish a wireless personal area network (WPAN). Inyet another embodiment, the base station 114 b and the WTRUs 102 c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. Asshown in FIG. 1A, the base station 114 b may have a direct connection tothe Internet 110. Thus, the base station 114 b may not be required toaccess the Internet 110 via the CN 106/115.

The RAN 104/113 may be in communication with the CN 106/115, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. The data may have varying qualityof service (QoS) requirements, such as differing throughputrequirements, latency requirements, error tolerance requirements,reliability requirements, data throughput requirements, mobilityrequirements, and the like. The CN 106/115 may provide call control,billing services, mobile location-based services, pre-paid calling,Internet connectivity, video distribution, etc., and/or performhigh-level security functions, such as user authentication. Although notshown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or theCN 106/115 may be in direct or indirect communication with other RANsthat employ the same RAT as the RAN 104/113 or a different RAT. Forexample, in addition to being connected to the RAN 104/113, which may beutilizing a NR radio technology, the CN 106/115 may also be incommunication with another RAN (not shown) employing a GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

The CN 106/115 may also serve as a gateway for the WTRUs 102 a, 102 b,102 c, 102 d to access the PSTN 108, the Internet 110, and/or the othernetworks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) and/orthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired and/or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another CN connected to one or more RANs, whichmay employ the same RAT as the RAN 104/113 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities (e.g., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks). For example, the WTRU 102 c shown in FIG. 1A may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram illustrating an example WTRU 102. As shownin FIG. 1B, the WTRU 102 may include a processor 118, a transceiver 120,a transmit/receive element 122, a speaker/microphone 124, a keypad 126,a display/touchpad 128, non-removable memory 130, removable memory 132,a power source 134, a global positioning system (GPS) chipset 136,and/or other peripherals 138, among others. It will be appreciated thatthe WTRU 102 may include any sub-combination of the foregoing elementswhile remaining consistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In an embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and/or receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

Although the transmit/receive element 122 is depicted in FIG. 1B as asingle element, the WTRU 102 may include any number of transmit/receiveelements 122. More specifically, the WTRU 102 may employ MIMOtechnology. Thus, in one embodiment, the WTRU 102 may include two ormore transmit/receive elements 122 (e.g., multiple antennas) fortransmitting and receiving wireless signals over the air interface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as NR and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs and/or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, a Virtual Reality and/or Augmented Reality (VR/AR) device, anactivity tracker, and the like. The peripherals 138 may include one ormore sensors, the sensors may be one or more of a gyroscope, anaccelerometer, a hall effect sensor, a magnetometer, an orientationsensor, a proximity sensor, a temperature sensor, a time sensor; ageolocation sensor; an altimeter, a light sensor, a touch sensor, amagnetometer, a barometer, a gesture sensor, a biometric sensor, and/ora humidity sensor.

The WTRU 102 may include a full duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for both the UL (e.g., for transmission) anddownlink (e.g., for reception) may be concurrent and/or simultaneous.The full duplex radio may include an interference management unit 139 toreduce and or substantially eliminate self-interference via eitherhardware (e.g., a choke) or signal processing via a processor (e.g., aseparate processor (not shown) or via processor 118). In an embodiment,the WTRU 102 may include a half-duplex radio for which transmission andreception of some or all of the signals (e.g., associated withparticular subframes for either the UL (e.g., for transmission) or thedownlink (e.g., for reception)).

FIG. 10 is a system diagram illustrating the RAN 104 and the CN 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the CN 106.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and/or receive wireless signals from, the WTRU 102a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the UL and/or DL, and the like. As shown in FIG. 10, the eNode-Bs 160a, 160 b, 160 c may communicate with one another over an X2 interface.

The CN 106 shown in FIG. 10 may include a mobility management entity(MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN)gateway (or PGW) 166. While each of the foregoing elements are depictedas part of the CN 106, it will be appreciated that any of these elementsmay be owned and/or operated by an entity other than the CN operator.

The MME 162 may be connected to each of the eNode-Bs 162 a, 162 b, 162 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM and/or WCDMA.

The SGW 164 may be connected to each of the eNode Bs 160 a, 160 b, 160 cin the RAN 104 via the S1 interface. The SGW 164 may generally route andforward user data packets to/from the WTRUs 102 a, 102 b, 102 c. The SGW164 may perform other functions, such as anchoring user planes duringinter-eNode B handovers, triggering paging when DL data is available forthe WTRUs 102 a, 102 b, 102 c, managing and storing contexts of theWTRUs 102 a, 102 b, 102 c, and the like.

The SGW 164 may be connected to the PGW 166, which may provide the WTRUs102 a, 102 b, 102 c with access to packet-switched networks, such as theInternet 110, to facilitate communications between the WTRUs 102 a, 102b, 102 c and IP-enabled devices.

The CN 106 may facilitate communications with other networks. Forexample, the CN 106 may provide the WTRUs 102 a, 102 b, 102 c withaccess to circuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. For example, the CN 106 may include,or may communicate with, an IP gateway (e.g., an IP multimedia subsystem(IMS) server) that serves as an interface between the CN 106 and thePSTN 108. In addition, the CN 106 may provide the WTRUs 102 a, 102 b,102 c with access to the other networks 112, which may include otherwired and/or wireless networks that are owned and/or operated by otherservice providers.

Although the WTRU is described in FIGS. 1A-1D as a wireless terminal, itis contemplated that in certain representative embodiments that such aterminal may use (e.g., temporarily or permanently) wired communicationinterfaces with the communication network.

In representative embodiments, the other network 112 may be a WLAN.

A WLAN in Infrastructure Basic Service Set (BSS) mode may have an AccessPoint (AP) for the BSS and one or more stations (STAs) associated withthe AP. The AP may have an access or an interface to a DistributionSystem (DS) or another type of wired/wireless network that carriestraffic in to and/or out of the BSS. Traffic to STAs that originatesfrom outside the BSS may arrive through the AP and may be delivered tothe STAs. Traffic originating from STAs to destinations outside the BSSmay be sent to the AP to be delivered to respective destinations.Traffic between STAs within the BSS may be sent through the AP, forexample, where the source STA may send traffic to the AP and the AP maydeliver the traffic to the destination STA. The traffic between STAswithin a BSS may be considered and/or referred to as peer-to-peertraffic. The peer-to-peer traffic may be sent between (e.g., directlybetween) the source and destination STAs with a direct link setup (DLS).In certain representative embodiments, the DLS may use an 802.11e DLS oran 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS)mode may not have an AP, and the STAs (e.g., all of the STAs) within orusing the IBSS may communicate directly with each other. The IBSS modeof communication may sometimes be referred to herein as an “ad-hoc” modeof communication.

When using the 802.11ac infrastructure mode of operation or a similarmode of operations, the AP may transmit a beacon on a fixed channel,such as a primary channel. The primary channel may be a fixed width(e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling.The primary channel may be the operating channel of the BSS and may beused by the STAs to establish a connection with the AP. In certainrepresentative embodiments, Carrier Sense Multiple Access with CollisionAvoidance (CSMA/CA) may be implemented, for example in in 802.11systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, maysense the primary channel. If the primary channel is sensed/detectedand/or determined to be busy by a particular STA, the particular STA mayback off. One STA (e.g., only one station) may transmit at any giventime in a given BSS.

High Throughput (HT) STAs may use a 40 MHz wide channel forcommunication, for example, via a combination of the primary 20 MHzchannel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHzwide channel.

Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz,and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may beformed by combining contiguous 20 MHz channels. A 160 MHz channel may beformed by combining 8 contiguous 20 MHz channels, or by combining twonon-contiguous 80 MHz channels, which may be referred to as an 80+80configuration. For the 80+80 configuration, the data, after channelencoding, may be passed through a segment parser that may divide thedata into two streams. Inverse Fast Fourier Transform (IFFT) processing,and time domain processing, may be done on each stream separately. Thestreams may be mapped on to the two 80 MHz channels, and the data may betransmitted by a transmitting STA. At the receiver of the receiving STA,the above described operation for the 80+80 configuration may bereversed, and the combined data may be sent to the Medium Access Control(MAC).

Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. Thechannel operating bandwidths, and carriers, are reduced in 802.11af and802.11ah relative to those used in 802.11n, and 802.11ac. 802.11afsupports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space(TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and16 MHz bandwidths using non-TVWS spectrum. According to a representativeembodiment, 802.11ah may support Meter Type Control/Machine-TypeCommunications, such as MTC devices in a macro coverage area. MTCdevices may have certain capabilities, for example, limited capabilitiesincluding support for (e.g., only support for) certain and/or limitedbandwidths. The MTC devices may include a battery with a battery lifeabove a threshold (e.g., to maintain a very long battery life).

WLAN systems, which may support multiple channels, and channelbandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include achannel which may be designated as the primary channel. The primarychannel may have a bandwidth equal to the largest common operatingbandwidth supported by all STAs in the BSS. The bandwidth of the primarychannel may be set and/or limited by a STA, from among all STAs inoperating in a BSS, which supports the smallest bandwidth operatingmode. In the example of 802.11ah, the primary channel may be 1 MHz widefor STAs (e.g., MTC type devices) that support (e.g., only support) a 1MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes.Carrier sensing and/or Network Allocation Vector (NAV) settings maydepend on the status of the primary channel. If the primary channel isbusy, for example, due to a STA (which supports only a 1 MHz operatingmode), transmitting to the AP, the entire available frequency bands maybe considered busy even though a majority of the frequency bands remainsidle and may be available.

In the United States, the available frequency bands, which may be usedby 802.11ah, are from 902 MHz to 928 MHz. In Korea, the availablefrequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the availablefrequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidthavailable for 802.11ah is 6 MHz to 26 MHz depending on the country code.

FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115according to an embodiment. As noted above, the RAN 113 may employ an NRradio technology to communicate with the WTRUs 102 a, 102 b, 102 c overthe air interface 116. The RAN 113 may also be in communication with theCN 115.

The RAN 113 may include gNBs 180 a, 180 b, 180 c, though it will beappreciated that the RAN 113 may include any number of gNBs whileremaining consistent with an embodiment. The gNBs 180 a, 180 b, 180 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the gNBs 180 a, 180 b, 180 c may implement MIMO technology. For example,gNBs 180 a, 108 b may utilize beamforming to transmit signals to and/orreceive signals from the gNBs 180 a, 180 b, 180 c. Thus, the gNB 180 a,for example, may use multiple antennas to transmit wireless signals to,and/or receive wireless signals from, the WTRU 102 a. In an embodiment,the gNBs 180 a, 180 b, 180 c may implement carrier aggregationtechnology. For example, the gNB 180 a may transmit multiple componentcarriers to the WTRU 102 a (not shown). A subset of these componentcarriers may be on unlicensed spectrum while the remaining componentcarriers may be on licensed spectrum. In an embodiment, the gNBs 180 a,180 b, 180 c may implement Coordinated Multi-Point (CoMP) technology.For example, WTRU 102 a may receive coordinated transmissions from gNB180 a and gNB 180 b (and/or gNB 180 c).

The WTRUs 102 a, 102 b, 102 c may communicate with gNBs 180 a, 180 b,180 c using transmissions associated with a scalable numerology. Forexample, the OFDM symbol spacing and/or OFDM subcarrier spacing may varyfor different transmissions, different cells, and/or different portionsof the wireless transmission spectrum. The WTRUs 102 a, 102 b, 102 c maycommunicate with gNBs 180 a, 180 b, 180 c using subframe or transmissiontime intervals (TTIs) of various or scalable lengths (e.g., containingvarying number of OFDM symbols and/or lasting varying lengths ofabsolute time).

The gNBs 180 a, 180 b, 180 c may be configured to communicate with theWTRUs 102 a, 102 b, 102 c in a standalone configuration and/or anon-standalone configuration. In the standalone configuration, WTRUs 102a, 102 b, 102 c may communicate with gNBs 180 a, 180 b, 180 c withoutalso accessing other RANs (e.g., such as eNode-Bs 160 a, 160 b, 160 c).In the standalone configuration, WTRUs 102 a, 102 b, 102 c may utilizeone or more of gNBs 180 a, 180 b, 180 c as a mobility anchor point. Inthe standalone configuration, WTRUs 102 a, 102 b, 102 c may communicatewith gNBs 180 a, 180 b, 180 c using signals in an unlicensed band. In anon-standalone configuration WTRUs 102 a, 102 b, 102 c may communicatewith/connect to gNBs 180 a, 180 b, 180 c while also communicatingwith/connecting to another RAN such as eNode-Bs 160 a, 160 b, 160 c. Forexample, WTRUs 102 a, 102 b, 102 c may implement DC principles tocommunicate with one or more gNBs 180 a, 180 b, 180 c and one or moreeNode-Bs 160 a, 160 b, 160 c substantially simultaneously. In thenon-standalone configuration, eNode-Bs 160 a, 160 b, 160 c may serve asa mobility anchor for WTRUs 102 a, 102 b, 102 c and gNBs 180 a, 180 b,180 c may provide additional coverage and/or throughput for servicingWTRUs 102 a, 102 b, 102 c.

Each of the gNBs 180 a, 180 b, 180 c may be associated with a particularcell (not shown) and may be configured to handle radio resourcemanagement decisions, handover decisions, scheduling of users in the ULand/or DL, support of network slicing, dual connectivity, interworkingbetween NR and E-UTRA, routing of user plane data towards User PlaneFunction (UPF) 184 a, 184 b, routing of control plane informationtowards Access and Mobility Management Function (AMF) 182 a, 182 b andthe like. As shown in FIG. 1D, the gNBs 180 a, 180 b, 180 c maycommunicate with one another over an Xn interface.

The CN 115 shown in FIG. 1D may include at least one AMF 182 a, 182 b,at least one UPF 184 a, 184 b, at least one Session Management Function(SMF) 183 a, 183 b, and possibly a Data Network (DN) 185 a, 185 b. Whileeach of the foregoing elements are depicted as part of the CN 115, itwill be appreciated that any of these elements may be owned and/oroperated by an entity other than the CN operator.

The AMF 182 a, 182 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N2 interface and may serve as acontrol node. For example, the AMF 182 a, 182 b may be responsible forauthenticating users of the WTRUs 102 a, 102 b, 102 c, support fornetwork slicing (e.g., handling of different PDU sessions with differentrequirements), selecting a particular SMF 183 a, 183 b, management ofthe registration area, termination of NAS signaling, mobilitymanagement, and the like. Network slicing may be used by the AMF 182 a,182 b in order to customize CN support for WTRUs 102 a, 102 b, 102 cbased on the types of services being utilized WTRUs 102 a, 102 b, 102 c.For example, different network slices may be established for differentuse cases such as services relying on ultra-reliable low latency (URLLC)access, services relying on enhanced massive mobile broadband (eMBB)access, services for machine type communication (MTC) access, and/or thelike. The AMF 162 may provide a control plane function for switchingbetween the RAN 113 and other RANs (not shown) that employ other radiotechnologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP accesstechnologies such as WiFi.

The SMF 183 a, 183 b may be connected to an AMF 182 a, 182 b in the CN115 via an N11 interface. The SMF 183 a, 183 b may also be connected toa UPF 184 a, 184 b in the CN 115 via an N4 interface. The SMF 183 a, 183b may select and control the UPF 184 a, 184 b and configure the routingof traffic through the UPF 184 a, 184 b. The SMF 183 a, 183 b mayperform other functions, such as managing and allocating UE IP address,managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may beIP-based, non-IP based, Ethernet-based, and the like.

The UPF 184 a, 184 b may be connected to one or more of the gNBs 180 a,180 b, 180 c in the RAN 113 via an N3 interface, which may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between the WTRUs 102a, 102 b, 102 c and IP-enabled devices. The UPF 184, 184 b may performother functions, such as routing and forwarding packets, enforcing userplane policies, supporting multi-homed PDU sessions, handling user planeQoS, buffering downlink packets, providing mobility anchoring, and thelike.

The CN 115 may facilitate communications with other networks. Forexample, the CN 115 may include, or may communicate with, an IP gateway(e.g., an IP multimedia subsystem (IMS) server) that serves as aninterface between the CN 115 and the PSTN 108. In addition, the CN 115may provide the WTRUs 102 a, 102 b, 102 c with access to the othernetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers. In oneembodiment, the WTRUs 102 a, 102 b, 102 c may be connected to a localData Network (DN) 185 a, 185 b through the UPF 184 a, 184 b via the N3interface to the UPF 184 a, 184 b and an N6 interface between the UPF184 a, 184 b and the DN 185 a, 185 b.

In view of FIGS. 1A-1D, and the corresponding description of FIGS.1A-1D, one or more, or all, of the functions described herein withregard to one or more of: WTRU 102 a-d, Base Station 114 a-b, eNode-B160 a-c, MME 162, SGW 164, PGW 166, gNB 180 a-c, AMF 182 a-ab, UPF 184a-b, SMF 183 a-b, DN 185 a-b, and/or any other device(s) describedherein, may be performed by one or more emulation devices (not shown).The emulation devices may be one or more devices configured to emulateone or more, or all, of the functions described herein. For example, theemulation devices may be used to test other devices and/or to simulatenetwork and/or WTRU functions.

The emulation devices may be designed to implement one or more tests ofother devices in a lab environment and/or in an operator networkenvironment. For example, the one or more emulation devices may performthe one or more, or all, functions while being fully or partiallyimplemented and/or deployed as part of a wired and/or wirelesscommunication network in order to test other devices within thecommunication network. The one or more emulation devices may perform theone or more, or all, functions while being temporarilyimplemented/deployed as part of a wired and/or wireless communicationnetwork. The emulation device may be directly coupled to another devicefor purposes of testing and/or may performing testing using over-the-airwireless communications.

The one or more emulation devices may perform the one or more, includingall, functions while not being implemented/deployed as part of a wiredand/or wireless communication network. For example, the emulationdevices may be utilized in a testing scenario in a testing laboratoryand/or a non-deployed (e.g., testing) wired and/or wirelesscommunication network in order to implement testing of one or morecomponents. The one or more emulation devices may be test equipment.Direct RF coupling and/or wireless communications via RF circuitry(e.g., which may include one or more antennas) may be used by theemulation devices to transmit and/or receive data.

In 5G New Radio (NR), to fulfill the high data rate requirements, above6 GHz frequency spectrum have been agreed to use in order to leveragethe large bandwidth. One of challenges in using these above 6 GHzfrequencies may be significant propagation loss, especially in anoutdoor environment due to higher free space path loss in a higherfrequency. A beamforming (e.g., analog beam) has been adopted to addressthe significant path loss in a higher frequency since it can compensatepath loss without increasing transmission power. As beams are used tocompensate the path loss, all downlink and uplink channels needs to bebased on beams. Thus, 5G NR downlink physical channels and downlinkcontrol channels need to be defined for the beam-based systems where thebeams are used for paging channels.

For paging, a WTRU may periodically monitor a physical downlink controlchannel (PDCCH) for a downlink control information (DCI) or downlink(DL) assignment on a PDCCH masked with a paging RNTI (P-RNTI), forexample, in idle mode and/or in connected mode. When a WTRU detects orreceives a DCI or DL assignment using a P-RNTI, the WTRU may demodulatethe associated or indicated physical downlink shared channel (PDSCH)resource blocks (RBs) and/or may decode a paging channel (PCH) that maybe carried on an associated or indicated PDSCH. A PDSCH carrying PCH maybe referred to as a PCH PDSCH. As used herein, the terms paging, pagingmessage, or PCH and variations thereof may be used interchangeablythroughout this disclosure.

For example, to receive paging message from the network, WTRUs in idlemode may monitor the PDCCH channel for an RNTI value used to indicatepaging (i.e. P-RNTI). The WTRU may need to monitor the PDCCH channel atcertain WTRU-specific occasions (i.e. at specific subframes withinspecific radio frames). At other times, the WTRU may apply discontinuousreception (DRX), meaning that it can switch off its receiver to preservebattery power. The network may configure which of the radio frames andsubframes are used for paging. Each cell may broadcast a default pagingcycle or a WTRU-specific paging cycle. The WTRU may calculate the radioframe (i.e. paging frame) and the subframe within that paging frame(i.e. paging occasion).

The paging frame (PF) and subframe within that PF (i.e. paging occasion)may be determined based on the WTRU ID (e.g., UE_ID) and parameterswhich may be specified by the network. The parameters may include, butare not limited to, the paging cycle (PC) length (e.g., in frames), andthe number of paging subframes per paging cycle (e.g., nB). The PClength may be the same as a DRX cycle. The number of paging subframesper paging cycle (e.g., nB) may enable the determination of the numberof PF per PC (e.g., N) and the number of PO per PF (e.g., Ns) which maybe in the cell. The WTRU ID, in an embodiment, may be the WTRU IMSI mod1024. The subframe within the PF may be the paging occasion (PO) that aWTRU may monitor for the paging channel, for example, in idle mode.

From the network perspective, there may be multiple PFs per paging cycleand multiple POs within a PF. For example, more than one subframe perpaging cycle may carry PDCCH masked with a P-RNTI. Additionally, fromthe WTRU perspective, a WTRU may monitor a PO per paging cycle, and sucha PO may be determined based on the parameters specified herein (e.g.,above). The parameters may be provided to the WTRU via systeminformation, dedicated signaling information, or the like. POs mayinclude pages for one or more specific WTRUs, or they may include systeminformation change pages which may be directed to each of the WTRUs. Inidle mode, a WTRU may receive pages for reasons such as an incoming callor system information update changes.

In connected mode, a WTRU may receive pages related to systeminformation change, for example. The WTRU may not receive WTRU-specificpages that may be used for an incoming call. As such, a WTRU in theconnected mode may not monitor a specific PO. Additionally, forfrequency division duplex (FDD), the PO subframes may be limited tocertain subframes such as subframes 0, 4, 5 and 9. For time divisionduplex (TDD), the PO subframes may be limited to certain subframes suchas subframes 0, 1, 5 and 6.

Discontinuous reception (DRX) is described herein. In idle mode (e.g.,RRC idle mode and/or EPS connection management (ECM) idle mode), a WTRUmay monitor for or listen to the paging message for incoming calls,system information change, Earthquake and Tsunami Warning Service (ETWS)notification for ETWS capable WTRUs, Commercial Mobile Alert System(CMAS) notification. Extended Access Barring parameters modification, orthe like.

A WTRU may monitor PDCCH for P-RNTI discontinuously, for example, toreduce battery consumption when there may be no pages for the WTRU. DRXmay be or include the process of monitoring PDCCH discontinuously. Inidle mode, DRX may be or include the process of monitoring PDCCHdiscontinuously for P-RNTI, for example to monitor for or listen to apaging message during RRC idle state.

As used herein, the terms idle mode, idle state, RRC idle mode, RRC idlestate, or RRC_IDLE mode/state may be used interchangeably throughoutthis disclosure. The terms RRC Idle and ECM Idle may also be usedinterchangeably throughout this disclosure. DRX can also be enabledand/or used in Connected Mode. When in Connected Mode, if DRX isconfigured, the MAC entity may monitor the PDCCH discontinuously, forexample using DRX operation. Connected Mode, Connected State, andRRC_CONNECTED mode or state may be used interchangeably. As used herein,the terms paging, paging message, or PCH and variations thereof may beused interchangeably throughout this disclosure.

Idle mode DRX is described herein. A WTRU may use one or more DRXparameters that may be broadcasted, for example, in a system informationblock (SIB) such as SIB2, to determine the PF and/or PO to monitor forpaging. Alternatively or additionally, the WTRU may use one or more WTRUspecific DRX cycle parameters that may be signaled to the WTRU, forexample by the MME through NAS signaling.

Table 1 provides examples of DRX parameters including example ranges andthe example source of the parameter (e.g., eNB or MME).

TABLE 1 Example DRX Cycle Parameters. DRX parameter Notation Value RangeConfiguring Network Node WTRU Specific DRX TUE 32, 4, 128 and 256 MME,e.g., via NAS cycle radio frames where signaling each radio frame may be10 ms Cell specific DRX TCELL 32, 4,128 and 256 eNB, e.g., via systemcycle radio frames information such as SIB2 Number of POs per nB 4T, 2T,T, T/2, T/4, eNB, e.g., via system DRX cycle, e.g., T/8, T/16, T/32information such as SIB2 DRX cycle across all where T may be the usersin the cell DRX cycle of the WTRU, for example, TCELL or the smaller ofTUE, if provided, and TCELL

The DRX cycle T of the WTRU may indicate the number of radio frames inthe paging cycle. A larger value of T may result in less WTRU batterypower consumption. A smaller value of T may increase WTRU battery powerconsumption. DRX cycle may be cell specific or WTRU specific.

A DRX cycle that is provided by the base station (BS) (e.g., eNB) may becell specific and may be provided to at least some (e.g., all) WTRUs ina cell. The DRX cycle that may be provided by the BS (e.g., eNB) may bethe default paging cycle. A DRX cycle provided by the MME may be a WTRUspecific. The WTRU may use the smaller among the default paging cycleand the WTRU specific DRX cycle as its DRX or paging cycle. An MME mayprovide a WTRU specific DRX cycle to a WTRU in NAS signaling, forexample as ‘a WTRU specific DRX cycle.’ An MME may provide a WTRUspecific DRX cycle to a BS (e.g., eNB) in a PAGING S1 AP message as‘Paging DRX’, for example, for an MME initiated paging message that maybe intended for the WTRU.

The WTRU and/or BS (e.g., eNB) may use the minimum between the defaultand specific DRX cycle. For example, T=Min (T_(UE),−T_(CELL)) in radioframes. A WTRU with DRX cycle of N (e.g., 128) radio frames may need towake up every N×frame time (e.g., 1.28 second for frame time of 10 ms)and look for a paging message.

The parameter nB (i.e. the number of paging subframe per paging cycle)may indicate the number of paging occasions in a cell specific DRXcycle. The parameter may be cell specific. Configuration of the nB valuemay depend on the paging capacity that may be desired or used in a cell.A larger value of nB may be used, for example, to increase pagingcapacity. A smaller value of nB may be used, for example, for a smallerpaging capacity.

The BS (e.g., eNB) and/or WTRU may calculate the WTRU's PFs according tothe following Equation (1):

PF=SFN mod T=(T div N)*(WTRU_ID mod N)  Equation (1)

where N is determined as N=min (T, nB). The WTRU specific PO within thePF may be determined from a set of paging subframes. The set may be afunction of predefined allowed subframes for paging and/or the number ofPOs per PF which may be a function of at least nB and/or T. System FrameNumber (SFN) may have a range of values such as 0 through 1023.

Connected mode DRX is described herein. In connected mode, a PF and POmay be determined in a similar manner as in idle mode. The DRX cycleparameters may be different for idle and connected modes. A WTRU maymonitor a (e.g., any) PO in a PC in connected mode, for example, toobtain system information change information.

It may be desirable to have longer DRX cycles such as extended DRX(eDRX) for devices such as machine type communication (MTC) devices. Inaddition, longer DRX cycles may be useful for some devices such as delaytolerant devices For example, it may reduce battery consumption and/orincrease battery life for those devices.

FIG. 2A illustrates an example 200 of timing for hyper frames (HFs) 205,210, 215, which may be used in any combination of other embodimentsdescribed herein. As illustrated in FIG. 2A, a time unit (e.g., hyperframes (HFs) 205, 210, 215) may be used with, as an extension of or ontop of radio frames and/or system frame number (SFN) timing (e.g.,legacy SFN timing). One HF 205, 210, 215 may include an SFN cycle 220,for example, 1024 radio frames or 10.24s. A HF 205, 210, 215 may have ahyper-system frame number (H-SFN). An H-SFN cycle 225 may include 1024SFN cycles 220. An H-SFN cycle 225 may last 1024*1024*10 ms (i.e. 174.76minutes).

An idle mode extended DRX (I-eDRX) cycle may include up to 256 H-SFNcycles 225. For example, an I-eDRX may last 256*1024*10 ms (i.e. 43.69minutes). The H-SFN cycle 225 may be broadcast by the cell. The H-SFNcycle 225 may increment at SFN cycle boundaries.

FIG. 2B illustrates an example 201 of paging within HFs 205, 210, 215,which may be used in any combination of other embodiments describedherein. The H-SFN in which a WTRU may become reachable for paging may bereferred to as a Paging hyper frame (PH) 235, 240 or as the WTRU's PH235, 240. A PH 235, 240 may be applicable (or only applicable) in ECMidle. A PH 235, 240 may be computed as a function of the extended DRXcycle and/or WTRU ID (e.g., IMSI mod (1024)). Within a PH 235, 240, thedetermination of the PF 250, 255, 260 and/or PO may follow the regularDRX rules and/or formulas. For example, a WTRU may receive a PF 250,255, 260 based on normal DRX cycle 245. A WTRU's paging window (PW) 265may be the window or time span corresponding to the set of PFs 250, 255,260 in the WTRU's PH 235, 240 during which the WTRU may monitor forpaging and/or may be paged. The PW 265 may include a subset of theavailable PFs 250, 255, 260 in the PH 235, 240. The PW 265 may besignaled to the WTRU, for example, by the MME in a NAS message. In a PF250, 255, 260, a WTRU may monitor (or only monitor) one PO. Paging to aWTRU may be repeated in one or more of a WTRU's PFs 250, 255, 260 in itsPW 265, for example, if the WTRU does not respond to a previous page.

A cell's support for the idle mode extended DRX (I-eDRX) may beimplicitly indicated by the broadcast of H-SFN. For long DRX cycles, itmay be useful for the MME to have some awareness of when the WTRUbecomes reachable, for example, to avoid storing paging requests at theBS (e.g., eNB) for a long time. In connected mode, the DRX cycle may beextended up to the SFN limit, for example, by extending the range ofvalues for long DRX cycle to 10.24 seconds.

FIG. 3 illustrates an example 300 of synchronization signal (SS) blocks315, 320, 325 within SS bursts 305, which may be used in any combinationof other embodiments described herein. A synchronization signal burst(SS burst) 305 may be used when multiple beams are used for initialaccess. For example, the SS burst 305 may be transmitted periodically(e.g., every 20 ms) and each SS burst 305 may include one or more SSblock 315, 320, 325. As illustrated in FIG. 3, one or more SS blocks(i.e. SS block #1 315, SS block #2 320, and SS block #3 325) may betransmitted periodically with x ms cycle. In addition, each of the SSblocks 315, 320, 325 may be associated with a beam. For example, if 64beams are used by a base station (BS), there may be 64 SS blocks whereeach beam includes an SS block 315, 320, 325 in its respectivetransmission. In another example, 64 SS blocks may be assigned to onebeam.

As illustrated in FIG. 3, an SS block 315, 320, 325 may include aprimary synchronization signal (PSS) 350, secondary synchronizationsignal (SSS) 355, and physical broadcast channel (PBCH) 360, 361, 362.After detecting the synchronization signals (i.e. PSS 350 and SSS 355),a WTRU may decode the PBCH 360, 361, 362, from which master informationblock (MIB) is obtained. The MIB may include a number of the mostfrequently transmitted parameters essential for initial access to thecell. In addition to MIB, the PBCH 360, 361, 362 may carry essentialinformation for an SS block 315, 320, 325 such as SS block specificconfiguration. The SS block specific configuration may include, but arenot limited to, an SS block number, a beam tracking area numberassociated with the SS block 315, 320, 325, and subsequent controlchannel configuration (e.g., PDCCH and PDSCH). Based on the SS blockspecific configuration, the WTRU may further receive broadcastingsignals associated with each SS block 315, 320, 325. For example, theWTRU may receive, via PDSCH, system information blocks (SIBs) associatedwith each SS block 315, 320, 325.

As described above, one or more SS blocks 315, 320, 325 in a SS burst305 may be associated with one or more beams. The number of SS blocks315, 320, 325 in a SS burst 305 may be determined by a BS (e.g., gNB)based on the number of beams used at the BS. In an example, if NB beamsare used at a BS (e.g., gNB), NB SS blocks 315, 320, 325 may be used ortransmitted in a SS burst 305. In a single SS burst 305, each SS block315, 320, 325 may include same or similar synchronization informationfor the PSS 350 and SSS 355. However, each SS block 315, 320, 325 mayinclude different configuration information (e.g., different SS blocknumber) for each PBCH 360, 361, 362 that is specific to the SS block315, 320, 325 associated with its respective beam.

As described above, in order to monitor paging messages, a downlinkcontrol channel (e.g., PDCCH or NR-PDCCH) needs to be configured ordefined for a WTRU in a beam-based system, wherein beams are used forpaging channels. In one embodiment, a WTRU may monitor a PDCCH orNR-PDCCH for paging message, wherein the PDCCH or NR-PDCCH resourceand/or search spaces may be configured, determined, or used in abeam-specific manner or a beam common manner.

A beam-specific paging occasion (PO) for the PDCCH or NR-PDCCH in abeam-specific system is described herein. A paging slot may be defined,used, or configured as a slot which may be potentially used for pagingchannel in NR. The paging slot may be configured with one or moreparameters including at least one of paging cycle, cell-ID, numerology(e.g., subcarrier spacing), slot length (e.g., regular slot ormini-slot), and frequency band (e.g., below 6 GHz or above 6 GHz). Asused herein, the term paging slot may be interchangeably used withpaging frame, cell-specific paging slot, and paging resources throughoutthis disclosure. The paging slot may include downlink controlchannel(s), such as PDCCH or NR-PDCCH, for paging monitoring anddownlink shared channel(s), such as PDSCH or NR-PDSCH, associated withthe paging slot. Specifically, a WTRU may monitor downlink controlchannels configured for paging monitoring. When the WTRU receives DCI inthe downlink control channel, the DCI may include paging information orscheduling information of PDSCH that may carry a paging message.Alternatively, the paging slot may include PDCCH or NR-PDCCH for pagingmonitoring only. As used herein, the term PDCCH may be interchangeablyused with NR-PDCCH, Control Resource Set (CORESET), search space, searchspace for paging, common search space, and common search space forpaging throughout this disclosure. The term PDSCH may be interchangeablyused with NR-PDSCH throughout this disclosure.

A paging block may be defined, used, or configured as a frequencyresource which may be potentially used for paging channel in NR. Thepaging block may be one or more frequency resource blocks which may beused for PDCCH or NR-PDCCH associated with paging channel. One or morepaging blocks may be located in a paging slot and configured with one ormore parameters including at least one of cell-ID, numerology (e.g.,subcarrier spacing), frequency band (e.g., below 6 GHz or above 6 GHz),system bandwidth, the number of paging blocks or the like. As usedherein, the term paging block may be interchangeably used with pagingfrequency resource, paging subband, paging narrowband, and pagingphysical resource block throughout this disclosure.

A paging resource may be defined, used, or configured with a time (e.g.,a paging slot) and frequency (e.g., a paging block) resources. Thepaging resource may be referred to as a PDCCH associated with an SSblock or more particularly, a common search space where a WTRU monitorsa paging DCI with a P-RNTI.

A paging occasion (PO) may be defined, used, or configured as a pagingresource in which a WTRU may monitor, attempt to decode, or receive aDCI associated with paging channel in a PDCCH or NR-PDCCH. The pagingoccasion may be considered as a paging resource configured or used for aWTRU or a group of WTRUs for the paging channel reception. The pagingoccasions for a WTRU or a group of WTRUs may be a subset of pagingresources. The subset of paging resources may be determined, configured,or used based on at least one of WTRU-specific parameters, cell-specificparameters, numerology, frequency band, or the like. Examples of theWTRU-specific parameters may include, but are not limited to, a WTRU-ID,DRX cycle, beam index, BPL index, and determined SS block such as SSblock index and SS block time location during initial access. Examplesof the cell-specific parameters may include, but are not limited to,paging resource configurations, paging slot cycle, and the like.Examples of numerology may include, but are not limited to, subcarrierspacing, cyclic prefix length, and the like. The frequency band may bebelow 6 GHz or above 6 GHz. In addition, one or more paging occasions(POs) may be configured or determined for a WTRU or a group of WTRUs,wherein the WTRU or the group of WTRUs may monitor a subset of POs.

In one embodiment, a paging slot may be configured or determined in abeam-specific manner by association between beams and POs. For example,a paging slot may be associated with a same beam for an SS block. One ormore SS blocks may be used in an SS burst and each SS block may beassociated with a beam or a beam pair link (BPL). Each SS block may alsobe associated with a paging slot which may be dedicated to the SS block.Specifically, a paging slot length may be aligned with SS block length.For example, if N_(sym) OFDM symbols are used for an SS block, thepaging slot length may be N_(sym) OFDM symbols.

The paging slot associated with an SS block may be located in the sameOFDM symbols used for the associated SS block. Specifically, at leastfor PDCCH or NR-PDCCH, the paging slot may be located in the same OFDMsymbols that may be used for the SS block. A subset of SS blocks or SSbursts may be used for the paging slot associated with an SS block. Forexample, if an SS block is transmitted every 20 ms, the paging slotassociated with the SS block may be configured as every 20×k ms, whereink may a positive integer number. The k value may be configured by a BS(e.g., gNB). For example, k value may be indicated in a broadcastingchannel or may be determined based on the number of SS blocks in an SSburst. The k value may be scaled based on the number of SS blocks in anSS burst, where the number of SS blocks in an SS burst may be indicatedin a broadcasting signal.

The subset of SS blocks for the paging slot may be determined from atleast one of cell-specific parameters, frequency band, number of OFDMsymbols, and the like. Specifically, the cell-specific parameters mayinclude at least one of a cell-specific paging cycle, system bandwidth,the number of paging blocks, cell-ID, and the like. The frequency bandmay be below 6 GHz and/or above 6 GHz. The number of OFDM symbols may beused for an SS block or PBCH in an SS block.

A WTRU may assume that the paging resource associated with an SS blockmay be quasi-co-located (QCL-ed) with the SS block (e.g., PSS, SSS,and/or DM-RS of PBCH in the SS block). Examples of the paging resourceassociated with the SS block may include, but are not limited to,demodulation-reference signal (DM-RS) of PDCCH or NR-PDCCH which may bemonitored by a WTRU for paging, or DM-RS of PDSCH or NR-PDSCH carryingpaging message. Specifically, TX and/or RX beam related information maybe QCL-ed between the SS block and its associated paging resource.Moreover, all QCL parameters (e.g., timing, Doppler spread, delayspread, beam, frequency, or the like) may be assumed to be QCL-ed forthe SS block and its associated paging resource.

The paging slot associated with an SS block may be indicated based on atime, frequency, and/or an offset from the SS block. PBCH in the SSblock may include the paging slot location related information in MIB orminimum system information (MSI). For example, MIB may contain a bitfield which may carry the paging slot related information. MSI mayinclude the paging slot location related information The MSI may bescheduled via a common PDCCH or NR-PDCCH which may be configured by MIB.The MSI may be beam-specific. Thus, MSI may be scheduled by itsassociated SS block. The common PDCCH or NR-PDCCH for MSI (or remainingminimum SI (RMSI)) may be used for paging channel as well. A WTRU maymonitor the common PDCCH or NR-PDCCH for MSI (or RMSI) and paging, wherethe DCI for MSI (or RMSI) and the DCI for paging may be identified by anRNTI. For example, a MSI-RNTI may be used to scramble CRC of the DCIused for MSI (or RMSI), and a P-RNTI may be used to scramble CRC of theDCI used for paging channel. The DCI size for MSI and paging channel maybe the same.

A time slot for common NR-PDCCH may be defined, configured, or usedbased on the SS block. For example, a time slot for a common NR-PDCCHmay have the same number of OFDM symbols used for an SS block. A commonNR-PDCCH may be associated with an SS block and the time slot for thecommon NR-PDCCH associated with an SS block may be located in the sameOFDM symbols used for the SS block. A time slot for common NR-PDCCH maybe interchangeably used with a paging slot if the common NR-PDCCH may beused for paging channel. The time slot for common NR-PDCCH may beinterchangeably used with a common NR-PDCCH time slot, a slot for commonNR-PDCCH, a common time slot, a beam-specific time slot, and abeam-specific common NR-PDCCH time slot.

FIG. 4 illustrates an example 400 of association types 405, 410, 412 fornew radio-physical downlink control channel (NR-PDCCH) andnew-radio-physical downlink control channel (NR-PDSCH), which may beused in any combination of other embodiments described herein. Asillustrated in FIG. 4, one or more association types 405, 410, 412 maybe used for NR-PDCCH and/or NR-PDSCH for broadcasting and pagingchannel. For example, a first type (e.g., type-A 405) may use time slotsfor NR-PDCCH 445 and NR-PDSCH 450 transmission. In the type-Aassociation 405, the NR-PDCCH 445 that is associated with the SS block#1415 may be first transmitted in a time slot. In the next time slot orlater time slot, the NR-PDSCH 450 that is associated with the NR-PDCCH445 (or the SS block#1 430) may be transmitted with x ms period. Asecond type (i.e. type-B 410) may use a time slot for both NR-PDCCH 455and its associated NR-PDSCH 460 transmission. In the type-B association410, the NR-PDCCH 455 and NR-PDSCH 460 associated with the SS block#1415 may be transmitted together in a time slot. In the next time slot orlater time slot, the NR-PDCCH 465 and NR-PDSCH 470 associated with theSS block#1 430 may be transmitted together. The NR-PDCCH 455 andNR-PDSCH 460 in the first time slot and the NR-PDCCH 465 and NR-PDSCH470 in the later time slot may be considered as paging occasions andeach paging occasion may include same or different paging information. Athird type (i.e. type-C 412) may use a time slot for NR-PDCCH 475 whileits associated NR-PDSCH 480 transmission may be indicated in the DCI ofthe NR-PDCCH 475. In the type-C association 412, the NR-PDCCH 475associated with the SS block#1 415 may be first transmitted in a timeslot. In a next time slot or later time slot, the NR-PDSCH 480associated with the NR-PDCCH 475 may be transmitted with y ms periodwhich may be indicated in the DCI of the NR-PDCCH 475 or predetermined.

The association type 405, 410, 412 described herein may be determinedbased on the downlink channel. For example, a first association type(i.e. type-A 405) may be used for MSI and a second association type(i.e. type-B 410) may be used for paging channel. The association typemay also be determined based on the frequency band. For example, a firstassociation type (i.e. type-A 405) may be used for above 6 GHz frequencyband and a second association type (i.e. type-B 410) may be used forbelow 6 GHz frequency band.

For the first type (i.e. type-A 405), the cycle of the time slots (e.g.,x ms) may be predetermined or configured via a broadcasting signal(e.g., MIB or MSI). For the second type (i.e. type-B 410), the frequencyresource allocated for NR-PDSCH 460, 470 may be indicated in theassociated NR-PDCCH 455, 465. For the third type (i.e. type-C 412), aWTRU may monitor NR-PDCCH 475 in a time slot which may be aligned withthe associated SS block (e.g., SS block#1 415) and its associatedNR-PDSCH 480 may be indicated in the DCI of the NR-PDCCH 475. Thecandidate time offsets for the associated NR-PDSCH 480 may be a timeslot which may not be overlapped with SS blocks 430, 435, 440 (or otherSS blocks which may not be associated with the NR-PDCCH).

In one embodiment, one or more control channel resource sets (CORESETs)may be configured in a paging time resource, wherein one or moreCORESETs may be located in a different frequency resource. A pagingfrequency resource (e.g., CORESET) of one or more frequency resources(e.g., CORESETs) may be used, determined, or configured for a WTRU or agroup WTRU to monitor for a paging message. The paging frequencyresource may be determined based on beam-related information.

A paging frequency resource may be determined based on an associated SSblock. For example, a modulo operation may be used based on the SS blocktime index and the number of paging frequency resources. Alternativelyor additionally, a paging frequency resource may be determined based onone or more beam indices which may be provided in a broadcasting signal.

In another embodiment, a single SS block may be associated with one ormore beams, wherein the number of beams used for a single SS block maybe indicated in an associated broadcasting signal. The one or more beamsused for an SS block may be referred to as a beam group (or a TX beamgroup). The number of frequency resources and its associatedconfiguration parameters may be transmitted in system information (e.g.,remaining minimum system information (RMSI) or other system information(OSI)).

In another embodiment, an NR-PDCCH resource (e.g., paging resource orDCI) may be common for all SS blocks and the NR-PDCCH resource may belocated over multiple SS blocks. The time slot for the associatedNR-PDSCH may be indicated in the NR-PDCCH, wherein the candidate timeslots for the associated NR-PDSCH may be based on the beam or BPL usedfor the NR-PDSCH. The time slot for the associated NR-PDSCH may beindicated with the SS block index. For example, if the NR-PDSCH istransmitted with a beam used for an SS block, the SS block index may beindicated in the NR-PDCCH and the SS block index may determine the timeslot containing NR-PDSCH.

In yet another embodiment, an NR-PDCCH resource for one or more ofminimum SI (MSI), other SI (OSI), RACH, and/or paging may be determinedbased on at least one of a time offset, a frequency offset, a cycle ofthe NR-PDCCH resource and the like. The time and frequency offsets maybe from the associated SS block. The time and frequency offsets may beindicated in PBCH in the associated SS block. The cycle of the NR-PDCCHresource may be used based on the default cycle (e.g., cycle of SS burstsuch as 20 ms).

A beam common paging occasion is described herein. A paging frame (or apaging slot, a paging occasion) may be defined, used, or configured in abeam-common manner. Therefore, one or more of POs may be determined orconfigured for a WTRU irrespective of an SS block selected, used, ordetermined by the WTRU. The paging frame (PF) may be considered orreferred to as a cell-specific paging resource. The paging occasion (PO)may be considered or referred to as a paging resource in which a WTRUmay monitor or attempt to receive a paging message.

The time resources for an SS burst may be used or configured for apaging frame. The SS burst may include one or more SS blocks and may betransmitted with a duty cycle. Therefore, the number of paging framesavailable or used in a time window may be determined based on the dutycycle of the SS burst. For example, if the duty cycle of the SS burst isshorter, a larger number of paging frame may be used.

In a paging frame (or paging occasion), a downlink control information(DCI) which may be used to schedule NR-PDSCH carrying paging message maybe transmitted or received over all beams used for SS blocks in an SSburst. For example, if N SS blocks are located in an SS burst, N controlchannel resource sets (e.g., CORESETs or NR-PDCCH CORESETs) may be usedor configured and each CORESET may be associated with an SS block. AWTRU may assume that the DCI may be repetitively transmitted over NCORESETs, wherein the same set of NR-PDCCH candidates (or set of controlchannel elements (CCEs)) may be used for the repetitive transmission ofthe DCI.

The subset of NR-PDCCH candidates (e.g., search space, a starting CCEindex) in each CORESET may be determined as a function of at least oneof following: (1) one or more of cell-specific parameters (e.g.,cell-ID, frame number, slot number, etc.); (2) one or more of SS blockspecific parameters (e.g., SS block time index, parameters indicated ina PBCH of the associated SS block); (3) P-RNTI (e.g., an RNTI used forpaging monitoring); (4) one or more of beam-related information (e.g.,beam identity index); and (5) a RX beam group (e.g., a WTRU maydetermine a set of Rx beams for paging reception. The RX beam group forpaging monitoring may be the latest RX beam group used before the WTRUfalls to an idle mode. If the RX beam group is changed, the WTRU mayupdate the RX beam group index (e.g., using PRACH resource).

A WTRU may determine to monitor a subset of CORESETs for pagingmonitoring. For example, a WTRU may first determine the subset ofCORESETs based on the measurement of SS blocks before it startsmonitoring paging or attempting paging reception. The WTRU may thenmonitor or attempt to receive paging message within the determinedsubset of CORESET(s). DM-RS of each CORESET may be QCL-ed with SSSand/or DM-RS of PBCH of the associated SS block.

In one embodiment, a DCI for scheduling of a NR-PDSCH carrying a pagingmessage may be used for a direct indication related to systeminformation update. Specifically, a flag bit in the DCI may be used toindicate whether the DCI carries NR-PDSCH scheduling information ordirect indication related information. If the flag bit is set to ‘TRUE’,the rest of DCI bits may be used for direct indication without NR-PDSCHscheduling information. If the flag bit is set to ‘FALSE’, the rest ofDCI bits may be used for NR-PDSCH scheduling. The direct indication mayinclude one or more of following: (1) system information update (e.g.,MIB, RMSI update and/or OSI update); (2) the number of SS block in an SSburst change or update; (3) update of SS burst duty cycle; (4) publicalarming (e.g., ETWS, CMAS, etc.); (5) configuration for grant-freeuplink resources update; and (6) update of a set of uplink resourcesassociated with the set of downlink beams (e.g., SS blocks). If a WTRUreceived a wake up signal, the WTRU may send beam-related information orselected beam indication by using the set of uplink resource indicatedor configured.

In another embodiment, a DCI may be used for NR-PDSCH scheduling, directindication and beam-related information update. For example, two flagbits may be used in the DCI. The first state of the flag (e.g., ‘00’)may be used to indicate that the DCI carries NR-PDSCH schedulinginformation. The second state of the flag (e.g., ‘01’) may be used toindicate that the DCI carries direct indication of system informationupdate without NR-PDSCH scheduling information. The third state of theflag (e.g., ‘10’) may be used to indicate that the DCI carriesbeam-related information update without NR-PDSCH scheduling information.The beam-related information may include at least one of following: (1)the number of SS blocks in an SS burst; (2) SS burst duty cycle; and (3)a set or subset of SS blocks turned off (or on/off SS block status). Forexample, a BS (e.g., gNB) may dynamically turn on/off of the SS blocks(e.g., beams) and the BS may indicate which SS blocks are on or off. Ifa WTRU has monitored an SS block which may be turned off, the WTRU maytrigger or start one or more of following procedures: new beam searchwithin an SS burst or initial cell search. The beam-related informationmay further include a TX beam group for common search space (orgroup-common NR-PDCCH).

A Multi-total radiated power (TRP) based paging occasion is describedherein. A WTRU may monitor POs associated with one or more TRPs toprovide robustness for the case that one or more beams are blocked in adynamic manner.

In one embodiment, one or more SS blocks in an SS burst may beassociated with a beam. If multiple SS blocks within an SS burst areassociated with a beam, the SS blocks may be assumed or considered asQCL-ed in terms of a beam. The SS blocks QCL-ed in terms of a beam mayindicate that PSS, SSS, and/or DM-RS of the SS blocks are QCL-ed interms of one or more QCL parameters (e.g., spatial Rx parameters).

FIG. 5 illustrates an example 500 of quasi-co-location (QCL) associationbetween SS blocks 515, 520, 525, 530, 535 in an SS burst 505 whenmultiple SS blocks 515, 530 are associated with a same beam 540, whichmay be used in any combination of other embodiments described herein. Asillustrated in FIG. 5, the SS block #1 515 and SS block #4 530 may beassociated with the same beam #3 540. Other SS blocks 520, 525, 535 maybe associated with another beam 545, 550, 560. For example, the SS block#2 520 may be associated with a beam #1 545, the SS block #3 525 may beassociated with a beam #550, and the SS block #N 535 may be associatedwith a beam #5 560. As illustrated in FIG. 5, the SS block #1 515 and SSblock #4 530 may be considered, assumed, or indicated as QCL-ed 575 atleast for a beam (e.g., the beam #3 540). However, the SS block #1 515and SS block #3 525 may be considered or assumed as non-QCL-ed 570 asdifferent beams (e.g., the beam #3 540 and the beam #2 550) areassociated with those SS blocks 515, 525. An SS block 515, 520, 525,530, 535 (e.g., SSS and/or DM-RS of PBCH in the SS block) and itsassociated POs (e.g., DM-RS of NR-PDCCH and/or NR-PDSCH for theassociated POs) may be QCL-ed. A WTRU may assume that an SS block 515,520, 525, 530, 535 and its associated POs may be QCL-ed.

In one embodiment, a BS may indicate the QCL association between SSblocks within an SS burst to a WTRU. For example, a subset of SS blocksassociated with a same beam may be indicated to a WTRU. Based on the QCLassociation, the WTRU may combine, accumulate, or use one or more SSblocks within an SS burst for higher accuracy of time/frequency trackingand/or beam measurement. Specifically, a minimum SI may include QCLassociation between SS blocks. One or more combinations or subsets of SSblocks may be predefined and at least one of the combinations or subsetsmay be indicated to the WTRU in the minimum SI. Moreover, PBCH in eachSS block may include QCL association information. For example, the SSblock indices which are used or associated with a same beam may beindicated in the MIB. If the number of SS blocks in an SS burst isN_(SS), N_(SS) bitmap may be used to indicate which SS blocks areassociated with the same beam. One or more subsets of SS blocks may bepredefined and at least one of the subsets may be indicated in the MIB.

A same sequence may be used for PSS or SSS to indicate which beam isassociated with. For example, a WTRU may detect a sequence used for PSSor SSS for one or more SS blocks. If the same sequence is used for oneor more SS blocks in an SS burst, the WTRU may assume that the SS blocksare QCL-ed or the SS blocks are associated with the same beam.

In another embodiment, a beam ID may be indicated in each SS block. Asdescribed above, an SS burst may include multiple SS blocks (e.g., up to64 SS blocks) and each SS block may be associated with a beam. Thus,there may exist multiple beams (e.g., up to 64 beams) associated withthe SS blocks. A bit field in a PBCH in an SS block may indicate whichbeam may be associated with the SS block. For example, 6 bits may beused to indicate a beam ID. This beam ID may be included in PBCH of eachSS block. If the beam ID is the same for two or more SS block, the WTRUmay assume or consider the two or more SS blocks are QCL-ed or the twoor more SS blocks are associated with the same beam. A WTRU may alsomeasure a beam quality from one or more SS blocks associated with thesame beam within an SS burst. Since a beam itself is transparent to theWTRU from the WTRU's perspective, the WTRU may measure the quality ofbeams using downlink signals (e.g., SS blocks). For example, the WTRUmay measure 64 beam qualities based on 64 downlink signals for the 64beams. A CRC of PBCH in each SS block may be masked with a beam ID.

A WTRU monitoring paging occasions (POs) with a beam group is describedherein. A PO may be determined based on a beam determined during initialaccess procedures. A WTRU may monitor POs which may be associated withone or more beams. Specifically, a WTRU may determine a subset of beams(e.g., one or more beams) from downlink signals (e.g., SS blocks). Thesubset of beams may be associated with multiple SS blocks (e.g., asubset of SS blocks) if the subset of beams includes more than one beam.Each beam in one or more subset of beams may be non-overlapped orpartially overlapped. The subset of beams may be interchangeably usedwith beam tracking area (BTA), beam group, paging beam group, pagingbeam tracking area, and paging beam subset.

One or more subsets of beams may be predetermined or predefined and asubset of beams may be selected or determined based on a beam qualitymeasurement of SS blocks. For example, a WTRU may measure beam qualityof SS blocks in all the subsets of beams and the WTRU may determine anSS block which provides the highest beam quality. The WTRU may thenselect the subset of beams in which the highest beam quality of the SSblock is included (or the SS block corresponding to the highest beamquality). A WTRU may also determine beam-specific POs for each beamwithin the selected subset of beams on the configuration information.

A WTRU may monitor POs associated with the subset of beams or subset ofSS blocks (or beam tracking area associated with the subset of beams orSS blocks). In a first type of monitoring POs, a WTRU may monitor allPOs associated with the subset of beams. In a second type of monitoringPOs, a WTRU may monitor a subset of POs associated with the subset ofbeams. Specifically, the subset of POs may be associated with a beam (ora best beam) which may have a highest beam quality within the subset ofbeams. The type of monitoring POs may be indicated by a network. Forexample, a network may indicate whether a WTRU may monitor a subset ofPOs associated with the subset of beams. If not, the WTRU may need tomonitor all POs associated with the subset of beams.

FIG. 6 illustrates an example 600 of beam tracking areas (BTAs) 617,627, 637, 647 for paging monitoring in an SS burst 605, which may beused in any combination of other embodiments described herein. Asillustrated in FIG. 6, a BS 610 may transmit multiple beams (i.e. beam a650, beam b 655, beam c 660, beam d 665, beam e 670, beam f 675, andbeam p 680). Each beam 650, 655, 660, 665, 670, 675, 680 may be spacedbased on vertical/horizontal domain. For example, the beam a 650 may bedirected at 90 degree vertical and 0 degree horizontal. The beam c 660may be directed at 90 degree vertical and 60 degree horizontal. Thus,the beam a 650 and beam c 660 may be placed at the same vertical domain,but different horizontal domain. Similarly, the beam e 670 may bedirected at 60 degree vertical and 0 degree horizontal. In this case,the beam a 650 and beam e 670 may be placed at the same horizontaldomain, but different vertical domain.

As described above, each beam 650, 655, 660, 665, 670, 675, 680 may beassociated with its respective SS block 615, 620, 625, 630, 635, 640,645. For example, as illustrated in FIG. 6, the beam a 650 may beassociated with SS block #1 615 and the beam b 655 may be associatedwith SS block #2 620. Similarly, the beam f 675 may be associated withSS block #6 640 and the beam p 680 may be associated with SS block #N645. One or more SS blocks 615, 620, 625, 630, 635, 640, 645 (or one ormore beams 650, 655, 660, 665, 670, 675, 680) may also be grouped into asubset of SS blocks (or a subset of beams) based on beam tracking area617, 627, 637, 647. For example, the SS block #1 615 and SS block #2 620may be grouped into a first subset of SS blocks that corresponds to beamtracking area #1 617. Since the SS block #1 615 is associated with thebeam a 650 and the SS block #2 620 is associated with the beam b 655,the subset of beams including the beam a 650 and b 655 may beinterchangeably referred to as beam tracking area #1 617. Similarly, theSS block #3 625 and SS block #4 630 may be grouped into a second subsetof SS blocks that corresponds to beam tracking area #2 627. The SS block#5 635 and SS block #6 640 may be grouped into a third subset of SSblocks that corresponds to beam tracking area #3 637. Thus, an SS burst605 may include K number of beam tracking area (from beam tracking area#1 617 to beam tracking area #K 647) based on the number of SS blocks615, 620, 625, 630, 635, 640, 645 and/or the number of beams 650, 655,660, 665, 670, 675, 680. As used herein, the term beam tracking area maybe interchangeably used with beam tracking area number or beam trackingarea index throughout this disclosure.

In one embodiment, a beam tracking area index may be used and each SSblock may include beam tracking area information. For example, the PBCHin an SS block may include beam tracking area index. Specifically, thenumber of beam tracking areas may be determined based on the number ofbeams used in an SS burst. The number of SS blocks in an SS burst mayalso be used to determine the number of beam tracking areas. The beamsin a beam tracking area may also be localized in the spatial domain(e.g., vertical and/or horizontal) as described above. Lastly, the beamsin a beam tracking area may be evenly distributed in the spatial domain.

FIG. 7 illustrates another example 700 of beam tracking areas (BTAs)717, 727 for paging monitoring in an SS burst 705, which may be used inany combination of other embodiments described herein. As illustrated inFIG. 7, the BS 710 may have N SS blocks in an SS burst 705 and each SSblock may be associated with a beam (e.g., 740, 745, 750, 755, 760).Although it is not shown in FIG. 7, the BS 710 may use up to N (e.g.,N=64) beams in an SS burst 705. Each beam 740, 745, 750, 755, 760 mayoccupy one time unit to transmit one paging resource (e.g., paging DCI)over PDCCH. This means that the BS 710 may transmit a same pagingresource 5 times over the 5 beams 740, 745, 750, 755, 760 to the WTRU toindicate the control channel (e.g., PDCCH) that the WTRU needs tomonitor for paging message.

As illustrated in FIG. 7, each beam 740, 745, 750, 755, 760 may beassociated with its respective SS block 715, 720, 725, 730, 735. Forexample, the beam1 740 and beam2 745 may be associated with SS block #1715 and SS block #2 720, respectively. The SS block #1 715 and SS block#2 720 may be grouped into a first subset of SS blocks that correspondsto beam tracking area #1 717. Similarly, the beam3 750 and beam4 755 maybe associated with SS block #3 725 and SS block #4 730, respectively.The SS block #3 725 and SS block #4 730 may be grouped into a secondsubset of SS blocks that corresponds to beam tracking area #2 727.Although it is not shown in FIG. 7, the WTRU may be configured withmultiple subsets of SS blocks associated with multiple beams. Forexample, if the BS 710 sweeps 64 beams in an SS burst 705, there may be8 subsets of SS blocks. In this case, each of the 8 subsets of SS blocksmay comprise 8 SS blocks that corresponds to its respective BTA. A setof SS blocks may comprise all the subsets of SS blocks including thefirst and second subsets of SS blocks. As used herein, the set of SSblocks may be interchangeably used with a group of SS blocks. The subsetof SS blocks may be interchangeably used with a subgroup of SS blocks.

In one embodiment, the WTRU may receive, from the BS 710, pagingresource and beam tracking area (BTA) configuration associated with thepaging resource. The BTA configuration may include, but are not limitedto, the number of BTAs 717, 727, and association information between:(1) the BTA 717, 727 and SS blocks 715, 720, 725, 730, 735, (2) the BTA717, 727 and subsets of SS blocks, (3) the BTA 717, 727 and beams 740,745, 750, 755, 760; or (4) the BTA 717, 727 and paging resourcesassociated with the beams 740, 745, 750, 755, 760 (or SS blocks 715,720, 725, 730, 735). The BTA configuration may be transmitted in abroadcasting message such as system information block (SIB), an RRCmessage or the like. The WTRU may receive the paging resource and BTAconfiguration while the WTRU is in idle mode (e.g., RRC idle) or inconnected mode (e.g., RRC connected).

Once the WTRU receives the paging resource and BTA configuration, theWTRU may monitor quality of beams 740, 745, 750, 755, 760 based ondownlink signal. For example, the quality of beams 740, 745, 750, 755,760 may be measured based on reference signal received power (RSRP),received signal strength indicator (RSSI), reference signal receivedquality (RSRQ), signal to interference plus noise ratio (SINR),hypothetical block error rate (BLER) of PDCCH, or the like. The WTRU mayperform the beam quality measurements for all the SS blocks 715, 720,725, 730, 735 associated with the beams 740, 745, 750, 755 760. The WTRUmay then select an SS block within all the SS blocks 715, 720, 725, 730,735 based on the beam quality measurements. For example, if the SS block#1 715 has the highest beam quality among all the SS blocks 715, 720,725, 730, 735 or meets the predetermined beam quality requirement, theWTRU may select the SS block #1 715 for its best quality beam. The WTRUmay then determine the BTA number (i.e. first BTA) associated with theselected SS block (or the subset of SS blocks that includes the selectedSS block) based on the BTA configuration. For example, if the SS block#1 715 is selected for its highest quality beam, the WTRU may determinethe BTA #1 717 to monitor the paging resource associated with the SSblock #1 715 (i.e. beam1 740). Alternatively or additionally, if theWTRU selects the first subset of SS blocks that includes the SS block #1715 as the beams that include the highest quality beam, the WTRU maydetermine the BTA #1 717 to monitor the paging resources associated withboth the SS block #1 715 and SS block #2 720 (i.e. beam1 740 and beam2745).

As described above, after determining the BTA number 717, 727, the WTRUmay monitor paging resources (e.g., paging DCI) associated with one ormore SS blocks 715, 720, 725, 730, 735. In this case, the WTRU mayreduce the number of SS blocks that the WTRU needs to monitor for pagingresources by monitoring the SS blocks 715, 720, 725, 730, 735 (or subsetof SS blocks) that corresponds to the determined BTA number 717, 727.For example, if a WTRU determines the BTA#1 717 as the BTA to monitorpaging resources, the WTRU may only need to monitor PDCCHs associatedwith the SS block #1 715 and the SS block #2 720. If the WTRU receivesDCI with P-RNTI from the PDCCH associated with the SS block #1 717 orthe SS block #2 720, the WTRU may demodulate PDSCH resource blocksindicated by the DCI. The WTRU may then decode the paging message (orPCH) carried on the PDSCH associated with DCI. Since the number of beams740, 745, 750, 755, 760 or SS blocks 715, 720, 725, 730, 735 that theWTRU needs to monitor is reduced by using the BTA 717, 727, the WTRU maysave its battery consumption and extend the batter duration.

While monitoring the paging resources associated with the selected beams740, 745, 750, 755, 760 or selected SS blocks 715, 720, 725, 730, 735based on the determined BTA number 717, 727, if the beam quality of theselected SS blocks 715, 720, 725, 730, 735 falls below a predeterminedthreshold or does not meet the predetermined beam quality requirement,the WTRU may trigger a BTA update procedure to indicate the BS 710 a newcandidate BTA or updated BTA. For example, if a WTRU initially selectsBTA #1 717 (i.e. SS block #1 715 and SS block #2 720) for pagingresource monitoring but the qualities of beams associated with the SSblock #1 715 and SS block #2 720 fall below a predetermined threshold,the WTRU may initiate beam quality measurements for all the SS blocks715, 720, 725, 730, 735 in the SS burst 705 or part of the SS blocks715, 720, 725, 730, 735 such as neighboring SS blocks (e.g., SS block #3725 and SS block #4 730). Based on the beam quality measurements forother SS blocks 715, 720, 725, 730, 735, the WTRU may select another SSblock (or a subset of SS blocks) that includes the highest quality ofbeam or meets the beam quality requirement. For example, if the WTRUselects the SS block #4 730 as the highest quality beam, the WTRU maydetermine BTA#2 727 as the BTA to be updated for paging resourcemonitoring. The WTRU may then monitor paging resources associated withthe updated BTA (i.e. BTA#2 727) or the SS block #3 725 and SS block #4730. The SS blocks associated with the updated BTA (i.e. SS block #3 725and SS block #4 730) may be referred to as a second subset of SS blocks.The predetermined threshold may be received from a BS 710 in abroadcasting message such as system information block (SIB), an RRCmessage or the like.

In order to indicate the updated BTA (i.e. second BTA) to the BS 710,the WTRU may use a random access channel (RACH) procedure. For example,the WTRU may transmit a signal (e.g., PRACH preamble) associated withthe updated BTA. The signal may include a physical random access channel(PRACH) resource of the SS blocks 715, 720, 725, 730, 735 that areassociated with the updated BTA (e.g., a second subset of SS blocks).The PRACH resource may include time and frequency resources for the SSblocks 715, 720, 725, 730, 735 associated with the updated BTA. ThePRACH resource may be determined from PRACH configuration informationreceived in a broadcasting message (e.g., SIB) from the BS 710. ThePRACH configuration information received from the BS 710 may includeassociation information between the PRACH resources and the SS blocks715, 720, 725, 730, 735.

Once the BS 710 received the signal indicating the updated BTA (i.e.second BTA), the BS 710 may determine which beam has the best quality tothe WTRU and select one or more beams 740, 745, 750, 755, 760 totransmit paging messages. Specifically, the BS 710 may select the SSblocks (i.e. the second subset of SS blocks) associated with the updatedBTA to transmit paging resources (e.g., DCI) over the PDCCHs. Using theupdated BTA, the WTRU may monitor the SS blocks (i.e. the second subsetof SS blocks) associated with the updated BTA. If the WTRU receives DCIwith P-RNTI from the PDCCHs associated with the updated BTA, the WTRUmay demodulate PDSCH resource blocks indicated by the DCI and decode thepaging message (or PCH) carried on the PDSCH.

As described above, a WTRU may monitor beam quality of the associatedbeam tracking area (BTA) based on a downlink signal (e.g., SS blocksassociated with the BTA). Specifically, a WTRU may monitor beam qualityof the associated BTA in each PO. The BTA may include one or more beams(e.g., one or more SS blocks). If the beam quality of all beams in a BTAis below a threshold, a WTRU may determine or declare as beam failure ofthe BTA. The beam quality may be based on reference signal receivedpower (RSRP) of the SS blocks associated with the BTA (e.g., RSRPmeasured from SSS and/or PBCH in the SS blocks) or the like. Thethreshold may be a predefined or a predetermined value.

If a WTRU determined or declared beam failure of the BTA, the WTRU maysearch a new candidate of BTA which meets the beam quality requirement.If a new candidate of BTA is found, the WTRU may change to new candidateof BTA; the WTRU may indicate or report the BTA change to the network.If a new candidate of BTA is not found, the WTRU may trigger or performinitial access procedure.

A BTA change indication or notification may be performed or used basedon at least one of PRACH resources, WTRU-ID, grant-free UL transmissionresources, or the like. Specifically, a set of PRACH resources may bereserved for BTA change indication or notification. Each PRACH resourcemay be associated with a BTA; a WTRU may determine a PRACH resourcewhich may be associated with determined or changed BTA. The set of PRACHresources may be dedicated to a WTRU. The set of PRACH resources mayalso be configured per BTA.

The WTRU-ID may be included or indicated when a WTRU transmit PRACH forBTA change indication. A WTRU may transmit a PUSCH associated with thePRACH, wherein the PUSCH may include the WTRU-ID; for example, theWTRU-ID may be IMSI, s-TMSI, modulo of IMSI or s-TMSI, or the like. ThePUSCH associated with the PRACH may be transmitted in a predeterminedtime/frequency resources which may be dedicated to each PRACH resourcesconfigured for BTA change indication or notification.

A set of the grant-free UL transmission resources may be used for BTAchange indication or notification. A grant-free UL transmission resourcemay comprise at least one of a sequence (e.g., PRACH sequence), data(e.g., PUSCH), and uplink control (e.g., PUCCH). A WTRU may monitor a BS(e.g., gNB) confirmation. For example, after a WTRU send BTA changeindication or notification, the WTRU may monitor PDCCH or NR-PDCCH forthe confirmation of BTA change in the determined or changed BTA.

In one embodiment, a beam related information for a WTRU may be storedat a network (e.g., MME or gNB). For example, the latest beam relatedinformation for a WTRU may be stored in a network for paging when theWTRU switched from RRC connected mode to RRC idle mode. The latest beamrelated information may include at least one of SS blocks, beam-ID, orbeam group ID. The SS block(s) may be associated with BTA. When a WTRUis paged, MME may provide beam-related information for the WTRU to a gNBwithin a paging tracking area.

In another embodiment, a BS (e.g., gNB) may trigger beam reporting forpaging transmission. For example, a common DCI or a group-common DCI maybe transmitted or monitored in a common PDCCH or common NR-PDCCH whichmay be used for all beams (or all BTAs), wherein the DCI may indicate ortrigger a beam reporting from a WTRU or a group of WTRUs.

The DCI may include a bit field which may trigger a beam reporting froma WTRU or a group of WTRUs. The group of WTRUs may be determined basedon the associated SS block. For example, WTRUs monitoring POs associatedwith an SS block may be determined as a group of the WTRU. If the DCItriggers beam reporting, the WTRUs monitoring POs associated with thesame SS block may report beams. A set of PRACH resources may be used forbeam reporting and the set of PRACH resources to use may be indicated inthe DCI. For example, one or more sets of PRACH resources for beamreporting may be preconfigured or predefined and one of the set may beindicated in the DCI when a beam reporting is triggered.

The DCI may also be monitored or received in a common paging occasion(PO) which may be monitored by all WTRUs. The time/frequency resource ofthe common PO may be configured or determined based on one or more ofpaging cycle or cell-specific parameters. The paging cycle may beconfigured via broadcasting. Examples of the cell-specific parametersmay include, but are not limited to, a cell-ID, slot length, slotnumber, frame number, and the like.

FIG. 8 illustrates an example procedure 800 for updating beam trackingarea (BTA) for paging monitoring. For example, at step 805, a WTRU mayreceive, from a base station (BS), a configuration of beam trackingareas (BTAs) that associates a set of synchronization signal (SS) blockswith each BTA. The set of SS blocks may comprise one or more subsets ofSS blocks. A subset of SS blocks may include one or more SS blocks. AnSS block in the set (or subset) of SS blocks may include a primarysynchronization signal (PSS), a secondary synchronization signal (SSS),and a physical broadcasting channel (PBCH) associated with the SS block.The WTRU may receive, via the PBCH associated with the SS block, amaster information block (MIB) that includes a configuration of the SSblock such as SS block number and subsequent control channel to furtherreceive broadcasting messages associated with the SS block. Theconfiguration of BTAs may include a number of BTAs, associationinformation between each of the BTAs and each of the SS blocks,association information between each of the BTAs and each of the subsetof SS blocks, and/or association information between the BTAs and theset of SS. The configuration of BTAs may be transmitted in abroadcasting message such as master information block (MIB), systeminformation block (SIB), an RRC message, or the like.

At step 810, the WTRU may select, based on measurements of beamsassociated with the SS blocks in the set of SS blocks, a first SS blockin a first subset of SS blocks. For example, the WTRU may measure thequality of beams associated with the SS blocks in the set of SS blocksbased on RSRP, RSSI, RSRQ, SINR, hypothetical block error rate (BLER) ofPDCCH or the like. If the WTRU finds an SS block that has the highestquality of beam or meets a quality requirement, the WTRU may select theSS block as the first SS block. The first SS block may be included inthe first subset of SS blocks.

At step 815, the WTRU may determine, based on the configuration of BTAs,the first BTA associated with the first subset of SS blocks. Forexample, since the first SS block is selected for its highest qualitybeam, the WTRU may determine the first subset of BTAs as the BTA (i.e.first BTA) to monitor the paging resource. The WTRU may recognize theassociation between the first subset of BTAs and the first BTA based onthe configuration of BTAs.

At step 820, the WTRU may monitor one or more physical downlink controlchannels (PDCCHs) for paging resources (e.g., DCI) associated with thefirst subset of SS blocks that corresponds to the first BTA. If at leastone measured quality of at least one beam associated with the firstsubset of SS blocks is less than a predetermined threshold (or does notmeet a beam quality requirement) at step 825, the WTRU may transmit, toa base station (BS), a signal indicating a second BTA (i.e. updated BTA)that is associated with a second subset of SS blocks at step 830. TheWTRU may determine, based on at least one measurement of at least onebeam associated the set of SS blocks, a second SS block in the secondsubset of SS blocks. The second SS block may be associated a beam thathas the highest beam quality or meets a quality requirement among theset of SS blocks. However, if the measured qualities of all beamsassociated with the first subset of SS blocks is greater than thepredetermined threshold at step 825, the WTRU may keep monitoring one ormore PDCCHs for paging resources (e.g., DCI) associated with the firstsubset of SS blocks that corresponds to the first BTA at step 820.

The signal indicating the second BTA (or updated BTA) may include aphysical random access channel (PRACH) resource associated with thesecond subset of SS blocks that corresponds to the second BTA. The PRACHresources associated with the second BTA may be selected based on apredetermined configuration (e.g., PRACH configuration information).Upon transmitting the second BTA, the WTRU may receive, from the BS, oneor more paging resources (e.g., paging DCI) associated with the secondBTA over PDCCH. Upon receiving the one or more paging resources, theWTRU may receive, from the BS, a paging message (or PCH) based on theone or more paging resources.

The paging channel has been used for other objectives than pagingmessage transmission. For example, the paging channel may be used forsystem information update indication such as SI update, ETWS, CMAS,extended access barring (EAB), or the like. However, in a beam-basedsystem, the SI update may include beam common SIs and beam-specific SIs.When a beam-specific SI is updated, triggering SI update for all WTRUsmay result in unnecessary WTRU battery consumption as those WTRUs notmonitoring the beam of which information is updated. In order not towake up WTRUs that are monitoring beams of which the system informationhas not been updated, a separate SI update indication for beam common SIand beam-specific SI may be needed. If a WTRU received beam common SIupdate indication, the WTRU may receive the updated SI for the beamcommon system information. If a WTRU received beam-specific SI updateindication, the WTRU may receive the updated SI for the beam-specificsystem information.

In one embodiment, one or more types of SI update indication may beused. For example, a first type of SI update indication (e.g., type-1SI) may be used to update a first subset of SI which may be beam commoninformation. A second type of SI update indication (e.g., type-2 SI) maybe used to update a second subset of SI which may be beam specificinformation.

Specifically, the first type of SI update indication (e.g., type-1 SI)may be transmitted in DCI in a common PO. The first type of SI updateindication may be used to update beam common system information and aWTRU may monitor the DCI regardless of the associated SS block forbeam-specific PO configured or determined. The common PO may betransmitted using a beam sweeping, wherein DCI may be transmitted withone or more beams corresponding to SS blocks in an SS burst. The commonPO may also be transmitted in a time/frequency resource that may bemutually exclusive to a time/frequency resource for beam-specific POs.The periodicity of time and frequency resources for the common PO may beexplicitly configured by a broadcasting signal. For example, the timeand frequency resources may be indicated based on the start or end of anSS burst. The time and frequency resources may be indicated with offsetsfrom the start or end of an SS burst, or a specific SS block (e.g., thefirst SS block). Each SS block may indicate the same time and frequencyresources for the common PO with a different time and frequency offsets.A bit flag may be used for the DCI to indicate whether the DCI carriesits associated PDSCH scheduling information or type-1 SI updateindication. When the DCI carries type-1 SI update indication, no PDSCHscheduling information may be transmitted in the DCI.

The second type of SI update indication (e.g., type-2 SI) may betransmitted in DCI in a beam-specific PO. The second type of SI updateindication may be used for beam-specific SI and a WTRU may monitor theDCI when the WTRU is determined to monitor the beam-specific PO.Specifically, each SS block may be associated with a beam and may haveits associated POs, wherein the DCI for type-2 SI update indication maybe monitored or received in the associated PO. A bit flag may be usedfor the DCI to indicate whether the DCI carries its associated PDSCHscheduling information or type-2 SI update indication. When the DCIcarries type-2 SI update indication, no PDSCH scheduling information maybe transmitted in the DCI.

In another embodiment, DCI in a common PO may be used to indicate bothfirst and second types of SI update indications. For example, DCI in acommon PO may include a type-1 SI update indication field and a type-2SI update indication field. A WTRU may monitor the DCI to reacquire thecorresponding SI if updated. If the type-1 SI update indicationindicates the type-1 SI update, all WTRUs may reacquire thecorresponding SI. If the type-2 SI update indication indicates thetype-2 SI updates, a WTRU may reacquire the corresponding SI if theupdated SI is associated with the current serving beam (e.g., SS blocksassociated with beam-specific POs).

The DCI in a common PO may carry type-1 SI update indication and/ortype-2 SI update indication field. In an example, an RNTI may be used toindicate which Type of SI update indication is transmitted in the DCI.For example, a first RNTI may be used to scramble CRC of the DCI if atype-1 SI update indication is transmitted. A second RNTI may be used toscramble CRC of the DCI if a type-2 SI update indication is transmitted.In another example, a type-1 SI update indication may be transmitted inthe DCI with a type-2 SI update indication associated with a beam or abeam tracking area (BTA). For example, one or more type-2 SI updateindications may be used for one or more beams or BTAs. In addition, theDCI may carry type-2 SI update indication of a beam or a BTA which maybe indicated at least one of an RNTI, type-I SI update indication, andthe like. The RNTI that may be used to scramble CRC of the DCI mayindicate which beam or BTA associated with the type-2 SI updateindication. The beam or BTA may be associated with SS block(s). Thetype-1 SI update indication may be located in the DCI irrespective ofwhich beam or BTA associated with the type-2 SI update indication.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

1. A method for use in a wireless transmit/receive unit (WTRU), themethod comprising: monitoring one or more physical downlink controlchannels (PDCCHs) for paging resources associated with a first subset ofsynchronization signal (SS) blocks that corresponds to a first beamtracking area (BTA); and on a condition that at least one measurement ofat least one beam associated with the first subset of SS blocks is lessthan a predetermined threshold, transmitting, to a base station (BS), asignal indicating a second BTA that is associated with a second subsetof SS blocks, wherein a set of SS blocks comprises the first subset ofSS blocks and the second subset of SS blocks.
 2. The method of claim 1,further comprising: receiving, from the BS, a configuration of BTAs thatincludes association information between each subset of the set of SSblocks and each of the BTAs; selecting, based on at least onemeasurement of at least one beam associated with the set of SS blocks, afirst SS block in the first subset of SS blocks; and determining, basedon the configuration of BTAs, the first BTA associated with the firstsubset of SS blocks.
 3. The method of claim 1, wherein the signalincludes a physical random access channel (PRACH) resource associatedwith the second subset of SS blocks that corresponds to the second BTA.4. The method of claim 1, further comprising: determining, based on atleast one measurement of at least one beam associated with the set of SSblocks, a second SS block in the second subset of SS blocks; andselecting, based on a predetermined configuration, the PRACH resourceassociated with the second BTA.
 5. The method of claim 1, wherein an SSblock in the set of SS blocks comprises a primary synchronization signal(PSS), a secondary synchronization signal (SSS), and a physicalbroadcasting channel (PBCH) associated with the SS block.
 6. The methodof claim 5, further comprising: receiving, via the PBCH associated withthe SS block, a master information block (MIB) that includes aconfiguration of the SS block.
 7. The method of claim 6, wherein theconfiguration of the SS block includes an SS block number.
 8. The methodof claim 1, further comprising: receiving, from the BS, one or morepaging resources associated with the second BTA; and receiving, from theBS, a paging message based on the one or more paging resources.
 9. Themethod of claim 8, wherein the one or more paging resources are includedin one or more downlink control information (DCI).
 10. The method ofclaim 1, wherein the signal indicating the second BTA is a PRACHpreamble.
 11. A wireless transmit/receive unit (WTRU) comprising: aprocessor configured to monitor one or more physical downlink controlchannels (PDCCHs) for paging resources associated with a first subset ofsynchronization signal (SS) blocks that corresponds to a first beamtracking area (BTA); and a transmitter configured to, on a conditionthat at least one measurement of at least one beam associated with thefirst subset of SS blocks is less than a predetermined threshold,transmit, to a base station (BS), a signal indicating a second BTA thatis associated with a second subset of SS blocks, wherein a set of SSblocks comprises the first subset of SS blocks and the second subset ofSS blocks.
 12. The WTRU of claim 11, further comprising: a receiverconfigured to receive, from the BS, a configuration of BTAs thatincludes association information between each subset of the set of SSblocks and each of the BTAs; the processor further configure to: select,based on at least one measurement of at least one beam associated withthe set of SS blocks, a first SS block in the first subset of SS blocks;and determine, based on the configuration of BTAs, the first BTAassociated with the first subset of SS blocks.
 13. The WTRU of claim 11,wherein the signal includes a physical random access channel (PRACH)resource associated with the second subset of SS blocks that correspondsto the second BTA.
 14. The WTRU of claim 11, wherein the processor isfurther configured to: determine, based on at least one measurement ofat least one beam associated with the set of SS blocks, a second SSblock in the second subset of SS blocks; and select, based on apredetermined configuration, the PRACH resource associated with thesecond BTA.
 15. The WTRU of claim 11, wherein an SS block in the set ofSS blocks comprises a primary synchronization signal (PSS), a secondarysynchronization signal (SSS), and a physical broadcasting channel (PBCH)associated with the SS block.
 16. The WTRU of claim 15, furthercomprising: a receiver configured to receive, via the PBCH associatedwith the SS block, a master information block (MIB) that includes aconfiguration of the SS block.
 17. The WTRU of claim 16, wherein theconfiguration of the SS block includes an SS block number.
 18. The WTRUof claim 11, further comprising: a receiver configured to: receive, fromthe BS, one or more paging resources associated with the second BTA; andreceive, from the BS, a paging message based on the one or more pagingresources.
 19. The WTRU of claim 18, wherein the one or more pagingresources are included in one or more downlink control information(DCI).
 20. The WTRU of claim 11, wherein the signal indicating thesecond BTA is a PRACH preamble.